A/N: Thanks for the comments. And Yes, obviously is an AU, that's what most of FF is. Chill out about the ages guys, its only fanfiction. Tony is like mid-thirties anyway, I've only made Tim younger. Remember guys, it's only Fanfiction! You don't like it, just don't read it. But to those who are interested or enjoying it, I look forward to seeing constructive critism, ideas, and just tell me what you think.

Ages, just so everyone is clear. Tim is 21, Tony 39.

Chapter Two

Tim kept shooting Tony nervous glances throughout the rest of the day. He was afraid that the elder man might say something to Gibbs or to anyone about his age. He was pretty sure Gibbs would flip if he found out that until today he had had a twenty-year-old on his team. He didn't think it would be much better now that he was twenty-one either.

Tony kept glancing at Tim for completely different reasons. He understood why he had lied to join the team, and why he had to keep on lying about it, but it was still hurtful. He had been ragging on a kid for the past few months! He could be no older than eighteen today, but he could even be younger, because there was no way on earth he was his own child. That was just too crazy, wasn't it? He put that thought in the deepest corner of his head, knowing he didn't want to think about it until he was faced with cold hard facts.

In the end Gibbs had gotten sick of the both staring at each other when one wasn't looking, he slammed his hands on the table getting both of their attention "For God's sake, leave the pair of you and sort out whatever needs to be sorted out."

"We're fine boss"

Gibbs glared at Tony, and he was quickly packing up his belongings, and another quick glare sent them both scampering into the lift.

The younger agent prayed that he wouldn't have to talk to the elder agent, but he knew that wouldn't happen and wasn't at all surprised when the lift came to a halt.

"How old are you?" Tony was straight to the point.

"Twenty-one… today." He said softly.

The Italian-American closed his eyes for a short time, trying to gather his thoughts. He tried to stop his mind doing the maths, but it was like saying not to think of a pink elephant, you couldn't help but think of it. He was thirty-nine, if Tim was twenty-one it had meant he would have been eighteen when he was born. And it was January, so it meant he could have been conceived in April. That was when he was dating Liz, he could remember because that was his birthday month and they had shared a romantic Birthday weekend together. Again, he pushed these thoughts to the deepest part of his mind. It was far too crazy to happen.

"I… I…"

Tony couldn't think straight now. It couldn't be true! He needed answers and he needed them now. He quickly flicked the elevator on and rushed out, leaving Tim standing there even more confused.

"Tim… son… I need to talk to you" Liz sat with her son in the restaurant, unsure of how she should tell him, and especially unsure of how he would take it.

He had never known anything about his father, and had begged her to tell him when he was younger. He had had a step-father, who was his younger sister Sarah's dad, but they had never gotten on well at all. So she knew this would come as a huge shock to him.

"Mom, I'm sorry I lied to get the job. But I didn't want to have to wait two years." He rubbed his neck.

"I understand why you did it, and I'm proud you are doing so well, even though I'm now going to be always worrying about you getting caught. But that's not why I want to talk to you" She took a large gulp of her glass of wine, trying to steady her self.

"Is it about you dating Tony?" Tim asked "Because he acted really weird before when I told him I was twenty-one."

"Yes…"

"Well, what is it?" The sandy-blond haired young man prompted her when she couldn't seem to find the words.

You see… Tim… The thing is… You know the reason I dropped out of collage?"

He nodded "Yeah, because you were pregnant with me and you didn't want to be a collage Mom, so you moved back in with Granddad and Grandma."

He had remembered asking her about college when he was picking his choices when he was sixteen. He had been curious to find out why she hadn't gone to college, especially when she was such a successful business woman.

"That wasn't the whole truth" She sighed "You see… I found out I was pregnant with you, and I was still dating your father, and I went to his dormitory to tell him"

He nodded, playing with the glass of wine in his hands nervously. This was the most she had ever told him of his dad, and he wasn't going to interrupt and make her stop now.

"Well… I found him" She smiled grimly "With another girl in bed, and I just ran. I need you to understand Timothy that I was only your age, I was scared, and I'm not proud of what I did. But I ran from that collage, and I never looked back."

"So… you never even told my father about me?" Tim was surprised at that. He had always thought his mom would have done that and his dad just didn't want to know him.

Liz shook her head "No, I'm sorry Tim. But you can tell him yourself if you want to, you've already met him and I'm sure if you don't say anything to him he'll figure it out himself"

"Who is it?" He racked his brains to think of all possible candidates, Tony never even crossed his mind.

"Timothy, I thought you were training to be an agent"

"I am but…" A thought struck his mind. Tony and his mom had dated, she said he knew them, and the agent had acted really odd when he found out his age. It couldn't be, could it? "Mom? Please don't tell me it is who I think it is?"

"Yes, Anthony Dinozzo is your father"

Even though he knew that was coming, he still choked on his wine.

Tony needed answers and he needed them now! The only place he knew where to find them, other than asking Liz and even then he would have wanted proof, was Abby's lab. He just hoped she could keep it on the down low.

He doubled back to NCIS, bringing an extra-large Café-Pow and a box of the lab rat's favourite chocolate muffins, presenting them to her with his best smile.

She looked at him suspiciously "What do you want Tony?"

"I need a small favour please Abby, and I need you to keep it quiet"

"This got something to do with Tim's mom? Kate told me you dated her. How weird is that? You were like Tim's step-dad at one point!" She had been ecstatic to find out that news, thinking it was cute.

"Abby, promise me you can keep this a secret" He grabbed both of her shoulders to stop her bouncing around, and showed him how serious this was.

"Cross my heart" She did the actions.

"I… I need you to do a paternity test. Between me … and McGee"

"Tony, you said you knew Tim as a kid. You know that you can't be his dad, right?" She was really confused now.

"That wasn't entirely true Abs. I knew his mom before he was born… exactly nine months before he was born if you get my drift"

Her eyes went wide, and for once she was speechless.

"Is this some sort of joke? Is Tony watching from somewhere? Because this really isn't funny!" He ran his hands through his hair, making it stick up wildly.

"No, it's no joke"

"Then… are you crazy? There's no way he's my father"

"I'm sorry Tim, but I know who the fathers of my children are, and he is yours." She told him, hoping he would take this better than she expected.

"I… I… he can't know! He will never ever let me live it down if he does." All he could think about was how much he was going to be ridiculed now.

She sighed "That's entirely your choice son. But I think he will have already caught on. That's probably why he freaked when you told him how old you were"

"When he asked you say you cheated on him with someone else! I don't know, just make something up! He can not know about this!"

"I won't lie if he asks me. He's your father, he does have a right to know"

"Then maybe you should have told him twenty-one years ago!" He shouted at her, uncaring that everyone around him was staring.

"Keep your voice down" She whispered at him, she didn't want to cause a scene.

Tim had gone past the point of being rational though, he was angry, scared and confused. This was possibly the worst birthday gift anyone could have given him.

"I'm out of here. Don't bother following me"

She watched sadly as her son stalked out of the restaurant. She really hoped he didn't do anything stupid.

"If he is yours, he really has your eyes." Abby commented, looking at the two pictures of the men on her computer side by side.

Tony ran a hand through his hair "But nothing else of mine. Look at him, he's the Probie. He's geeky, freakishly smart, pale skinned, I was a jock, more street smart and I'm Italian descent. He's got no Italian in him at all, and he's got none of me in him, he can't be mine."

"Not all kids are like their parents Tony. And even so, Tim's more like you than you think."

"Yeah" The Agent snorted.

"No really." She insisted "We all know that under that tough exterior of yours, you're really a sweet and caring guy. Tim's just not afraid to show it."

Tony shrugged. "He's a bit like his mother from what I can remember. She was insanely smart. But still, Tim is far from being like her"

"Like I said, not every kid is like their parents."

The computer beeped, interrupted their conversation to inform them it had the results. Before opening them Abby turned to Tony, she had something to ask before she let him see them.

"Whatever these say, if he is your son, if he isn't, you're not going to leave NCIS, or you're not going to start treating Tim unfairly, promise me?" This was as serious as Abby ever got, and the agent knew she meant business.

"Abs. I'm not like that. If Tim is…" He couldn't say the words, but he noticed he had started calling him Tim more often rather than Probie or McGee. "If he is… I'll face it. I'm not going to run away."

"Okay then…" She opened the file on the computer and in big read letters is read Positive match!

"Congratulations, you're a dad" The Goth jumped at him and pulled him in a big hug, while his face was still transfixed on those two words on the screen.

"I… uh… are you sure?"

"My lab never lies Tony, you should know that" She grinned, before thinking of something. "I know another think he gets from you too."

"What's that?"

"Well, he's really good with the ladies, once he gets on, if you get what I'm saying" She winked.

Tony tried to put that image out of his mind forever. "Abs, that's not something you should tell his father"

She laughed, while deleting the search of her computer. She knew this wasn't something that wanted to be found by the wrong people.

"You're right though" It was the Agent's turn to smile at her now "When I was twenty, there was no way I could pull a thirty-two year old." He clucked his tongue jokingly when her face dropped "Abigail Scuito, you dirty cougar."

"No… no… please tell me you're joking Tony! I'm going to kill him when I get my hands on him!"